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High rpm idle after resetting ecm, 1200rpm in drive
Need help, I had a check engine code come on p0441, probably just need a new charcoal canister. Anyway I disconnected the negative battery terminal for a few mins and reconnected it, but when I crank the engine it idles at 2200-2400 when the car is at normal operating temperature, then when I put it in drive the idle drops to 1100 or 1200. Is the computer relearning or should something be adjusted like throttle cable or transmission cable. I'm going to auto zone in the morning to pick up a battery and have the engine code pulled. Any advice or tips is greatly appreciated.
97Ls 180k miles. I replaced the ect on top of the engine 2 years ago, I bought it from auto zone, I also replaced the one in the radiator. The engine light came on last night on my way back home. I will have the code pulled this morning. All the vacuum hoses look fine.
The car was running perfectly fine yesterday UNTIL I pulled the negative battery terminal to reset the computer.
I will recheck all hoses. Should I completely disconnect the battery?
No need to disconnect the battery but it won't hurt. I would re-check the throttle cable to make sure that the cable isn't adjusted to tight. There is a tiny bit of slack which is easily adjusted and also check the cruise control cable adjustment for similar tension.
I have never adjusted the throttle cable or cruise control cable since I owned the car BUT for the past few weeks I have been adjusting the transmission cable via the adjustments nuts on top. I believe the repair manual calls for the metal budge to be 0-1mm from the stopper. Idk if the rubber cover is supposed to be pulled back or not.
Cruise and throttle cables do have a slight slack to them.
I pulled down the rubber then adjusted the nuts. 1mm is about the thickness of a dime or a penny.
Why don't you fix your P0441 problem first. This often causes a high rpm due to the vacuum leak at the vapor line.
Hmm I never thought that of that. I been having that p0441 for over 6 months the engine code goes on and off. I do smell slight gas fumes from front of the car, been like that for about a year.
I should mentioned this, about 2 months ago when I replaced my rack I changed my front o2 sensors but I used Bosch brand (my original o2 sensors were still working btw), and ever since then I been getting p0420 and p0430 codes. I plan to reinstall my old denso o2 sensors to get rid of those two codes.
Here are the symptoms I'm experiencing: almost 3k rpm on cold start and at operating temperature, and 1200 in drive. When I'm driving the car, the car will get up to 30-35 mph without me giving it gas, if I don't keep my foot on the brake pedal the car Will move forward on its own quickly.
The idle rpm is strictly controlled by the ECU but when there is any abnormal condition and it is out of the controllable range, the ECU gives it up. Once you disconnect the battery, the ECU relearns things. It sometimes needs nearly 30minutes of city driving if the abnormality is not within the range before.
This is just my assumption but your car must have some vacuum leak at the vapor line or the intake line. Sometimes you need a smoking machine to find the exact leaking (absorbing) point. A cigar is a cheap way but be careful for the cancer.
A cigar is a cheap way but be careful for the cancer.
I think you been watching Scotty Kilmer YouTube lol.. I thought about it but I would rather use a smoke machine.
But this is just a . Just a few a weeks ago I removed and cleaned the throttle body but I also disconnected the battery and the car started up and ran just fine.
I was reading online, some say it could be dirty or clogged IAC valve, vacuum leak, throttle pos sensor, or even a blown or malfunctioning fuse in electrical system causing the IAC to idle higher than normal. If I don't figure this out then off to my trusty Indy shop.
Why don't you fix your P0441 problem first. This often causes a high rpm due to the vacuum leak at the vapor line.
+1 fix that hose and check the remaining vacuum lines. One often leads to others being due for replacement. Then we can take the next step if that doesn't resolve the high idle.
I will check the vapor lines and around the charcoal canister. I might go pick up a used IAC valve from the wreck yard.
My local shop said it could be just the CPU trying to learn the throttle, and the idle might go back to normal after a few days or drive cycles, he said they had cars do this when they disconnected the battery.
I just had my battery disconnected for 2 dyas as I was putting in a new alternator, PS pump, new plugs and cleaned out the throttle body. I could not work on it full time. After reconnecting everything, started high for a couple of minutes but settled right in to normal RPMs pretty quickly.
Okay I'm embarrassed to post this, but I found why my car was idling so high.
It was a very very small piece of rubber preventing the throttle plate from completely closing, thus letting in extra air aka a vacuum leak. This also affected the TPS. The rubber came from the air intake when I was reinstalling my throttle body after cleaning it, I broke off a piece of rubber. Hopefully none went inside the engine, anyway the car is idling and driving just fine. In park it idles at 650.
No need to be embarassed ppl always forget to connect sensors and various other things when working on the engine. I always have to make sure that intake tube is seated correctly when reinstalling it.
03-18-15, 07:57 PM
High rpm idle after resetting ecm, 1200rpm in drive
. Just a few a weeks ago I removed and cleaned the throttle body but I also disconnected the battery and the car started up and ran just fine. 
